On Wed, 24 Sept 2025 at 14:00, Jinchao Wang <[email protected]> wrote: > > Introduce a separate test module to validate functionality in controlled > scenarios. > > The module provides a proc interface (/proc/kstackwatch_test) that allows > triggering specific test cases via simple commands: > > echo test0 > /proc/kstackwatch_test
This should not be in /proc/ - if anything, it should go into debugfs. > Test module is built with optimizations disabled to ensure predictable > behavior. > > Signed-off-by: Jinchao Wang <[email protected]> > --- > mm/Kconfig.debug | 10 ++++ > mm/kstackwatch/Makefile | 6 ++ > mm/kstackwatch/test.c | 122 ++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 138 insertions(+) > create mode 100644 mm/kstackwatch/test.c > > diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug > index 89be351c0be5..291dd8a78b98 100644 > --- a/mm/Kconfig.debug > +++ b/mm/Kconfig.debug > @@ -317,3 +317,13 @@ config KSTACK_WATCH > A lightweight real-time debugging tool to detect stack corrupting. > > If unsure, say N. > + > +config KSTACK_WATCH_TEST > + tristate "KStackWatch Test Module" > + depends on KSTACK_WATCH > + help > + This module provides controlled stack corruption scenarios to verify > + the functionality of KStackWatch. It is useful for development and > + validation of KStackWatch mechanism. > + > + If unsure, say N. > diff --git a/mm/kstackwatch/Makefile b/mm/kstackwatch/Makefile > index 84a46cb9a766..d007b8dcd1c6 100644 > --- a/mm/kstackwatch/Makefile > +++ b/mm/kstackwatch/Makefile > @@ -1,2 +1,8 @@ > obj-$(CONFIG_KSTACK_WATCH) += kstackwatch.o > kstackwatch-y := kernel.o stack.o watch.o > + > +obj-$(CONFIG_KSTACK_WATCH_TEST) += kstackwatch_test.o > +kstackwatch_test-y := test.o > +CFLAGS_test.o := -fno-inline \ > + -fno-optimize-sibling-calls \ > + -fno-pic -fno-pie -O0 -Og > diff --git a/mm/kstackwatch/test.c b/mm/kstackwatch/test.c > new file mode 100644 > index 000000000000..1ed98931cc51 > --- /dev/null > +++ b/mm/kstackwatch/test.c > @@ -0,0 +1,122 @@ > +// SPDX-License-Identifier: GPL-2.0 > +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt > + > +#include <linux/delay.h> > +#include <linux/kthread.h> > +#include <linux/list.h> > +#include <linux/module.h> > +#include <linux/prandom.h> > +#include <linux/printk.h> > +#include <linux/proc_fs.h> > +#include <linux/random.h> > +#include <linux/spinlock.h> > +#include <linux/string.h> > +#include <linux/uaccess.h> > + > +#include "kstackwatch.h" > + > +static struct proc_dir_entry *test_proc; > + > +#define BUFFER_SIZE 16 > +#define MAX_DEPTH 6 > + > +struct work_node { > + ulong *ptr; > + struct completion done; > + struct list_head list; > +}; > + > +static DECLARE_COMPLETION(work_res); > +static DEFINE_MUTEX(work_mutex); > +static LIST_HEAD(work_list); > + > +static void test_watch_fire(void) > +{ > + u64 buffer[BUFFER_SIZE] = { 0 }; > + > + pr_info("entry of %s\n", __func__); > + ksw_watch_show(); > + ksw_watch_fire(); > + pr_info("buf[0]:%lld\n", buffer[0]); > + > + barrier_data(buffer); > + pr_info("exit of %s\n", __func__); > +} > + > + > +static ssize_t test_proc_write(struct file *file, const char __user *buffer, > + size_t count, loff_t *pos) > +{ > + char cmd[256]; > + int test_num; > + > + if (count >= sizeof(cmd)) > + return -EINVAL; > + > + if (copy_from_user(cmd, buffer, count)) > + return -EFAULT; > + > + cmd[count] = '\0'; > + strim(cmd); > + > + pr_info("received command: %s\n", cmd); > + > + if (sscanf(cmd, "test%d", &test_num) == 1) { > + switch (test_num) { > + case 0: > + test_watch_fire(); > + break; > + default: > + pr_err("Unknown test number %d\n", test_num); > + return -EINVAL; > + } > + } else { > + pr_err("invalid command format. Use 'testN'.\n"); > + return -EINVAL; > + } > + > + return count; > +} > + > +static ssize_t test_proc_read(struct file *file, char __user *buffer, > + size_t count, loff_t *pos) > +{ > + static const char usage[] = "KStackWatch Simplified Test Module\n" > + "============ usage ==============\n" > + "Usage:\n" > + "echo test{i} > /proc/kstackwatch_test\n" > + " test0 - test watch fire\n"; > + > + return simple_read_from_buffer(buffer, count, pos, usage, > + strlen(usage)); > +} > + > +static const struct proc_ops test_proc_ops = { > + .proc_read = test_proc_read, > + .proc_write = test_proc_write, > +}; > + > +static int __init kstackwatch_test_init(void) > +{ > + test_proc = proc_create("kstackwatch_test", 0600, NULL, > &test_proc_ops); > + if (!test_proc) { > + pr_err("Failed to create proc entry\n"); > + return -ENOMEM; > + } > + pr_info("module loaded\n"); > + return 0; > +} > + > +static void __exit kstackwatch_test_exit(void) > +{ > + if (test_proc) > + remove_proc_entry("kstackwatch_test", NULL); > + pr_info("module unloaded\n"); > +} > + > +module_init(kstackwatch_test_init); > +module_exit(kstackwatch_test_exit); > + > +MODULE_AUTHOR("Jinchao Wang"); > +MODULE_DESCRIPTION("Simple KStackWatch Test Module"); > +MODULE_LICENSE("GPL"); > -- > 2.43.0 > > -- > You received this message because you are subscribed to the Google Groups > "kasan-dev" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion visit > https://groups.google.com/d/msgid/kasan-dev/20250924115931.197077-2-wangjinchao600%40gmail.com.
